Improvement in the preparation of paper-stock



fated emitir-r.

GEORGE E. MARSHALL, OF LOUISYILLE, KENTUCKY.

Lette/rs Patent No. 90,566, dated May 25, 1869.

IMPROVEMENT IN THE PREPARATION OI' PAPER-STOCK.

The Schedule' referred to in these Letters Patent and making part of the same.

To all whom it may concern:

Be it known ,that I, GEORGE E. MARSHALL, of Louisville, in tbe county of Jefferson, and State of Kentucky, have invented certain new and useful Improvements in the Preparation of Paper-Stock; and I do herebydeclare that the following is a full, clear,

f and exact ldescription thereof, reference being had to the accompanying drawings, making part of this specification, and to the letters of reference marked thereon, like. letters indicating. like parts, wherever they occur.

To enable others skilled in the art to construct and use my invention, I will proceed to describe it.

Myuvention relates to the preparation of paperstock, or the disintegration of librous material, preparatory to the working of it into paper; and

My invention consists in cooking the stock or material with ther-aid of superheated steam, applied directly thereto.

The drawings lrepresent a front elevation of an apparatus, such as I use in my improved process, the parts being shown partly in section, for the purpose of showing the internal construction.

It has long been customary to boil straw, wood, an similar 'fibrous material, in alkali, heated by means of ordinary steam, admitted into a chamber surrounding or separate from the compartment in which the alkaline solution and stock were placed.

Efforts have also been made to cook it by means of a pump, drawing from the reservoir a portion of the solution, and after forcing it through pipes in a furnace, thence back into the reservoir.

lo each of these plans, -and the various modifications thereoi' which have been tried, there are objections, which lny improvement is intended to obviate.

To cook the stock according to my improved plan, I provide a boiler, of any suit-able kind and size, for holding the stock, which in the drawings is represented as an upright iron boiler or vessel, G.

This boiler is provided with au inclined perforated bottom, and a discharge-spout, (l, which latter is closed by a sliding-gate, c, operated by a hand-wheel, b, which screws on a rod, a, attached to the gate, and extends up through the top, as shown in the drawings.

I then provide a boiler, A, of any suitable kindfor veying steam to the stock-boiler C.

Between these two boilers I locate a furnace, B, and

pass the steam-pipe D through it, as represented in the drawing, the pipe being coiled or otherwise arranged in-the furnace so as to expose a considerable part of it to the action of the heat,'whereby the steam shall be superheated.

From this furnace B the pipe D passes to the stockboiler C, which it enters, as represented.

In cooking the stock, I place it, with the alkaline solution, in the boiler O, there being a space of a foot:l

or more in the top of the boiler left unfilled.

Steam is then passed through the pipe D, and being super-heated in the furnace B, is conveyed into the boiler C, where it mingles 'with the stock and solution, and imparts to it a considerable degree of heat.

,The steam being super-heated, and converted into dry steam, does not add to the volume of material in the stock-boiler, asit would were it notl thus superheated, and by thus using superheat-ed steam I am enabled to impart to the stock the requisite degree. of heat, and to continue the process a suflcient length of time to cook the contents of the boiler C by the time that the same is full.

It is obvious that instead of a stationary stockboiler, a rotating one may be used, the superheatcd steam being used in the same manner.

I also propose to use superheated steam for cooking the stock in an open tub or boiler.

l have ascertained by actual experiment that paperstock can be eiectnally and speedily cooked in this manner, at less expense thanby any of the processes heretbfore used.

Having thus described my invention,

1. The herein-described process of preparing paperstock, that is to say, cooking or treating fibrous material in an alkaline solution, and introducing superheated steam directlyinto the vessel in which said material is being cooked or treated, substantially as described.

2. The combination of a boiler for generating steam, a furnace for superheating the steam, and -a vessel for cooking the stock, whenarranged to operate substantially as described.

' GEO. E. MARSHALL. Witnesses:

W. O. DODGE, P. T. DODGE. 

